In recent times, there has been a rapid increase in use of technologies such as virtual reality, augmented reality, and so forth, for presenting a simulated environment (or a simulated world) to a user. Typically, the user uses a device (for example, such as a virtual reality device, an augmented reality device, and the like) for experiencing such a simulated environment. Furthermore, in use, the user generally wears (namely, supports) the device on his/her head.
Nowadays, such devices often employ a technique such as gaze-tracking (namely, eye tracking) to determine a gaze direction of the user. Typically, the gaze-tracking is associated with determination of position of pupils of the user's eyes. Generally, an illumination source is employed for emitting light towards the user's eyes, and a camera is employed for capturing an image depicting the pupils of the user's eyes and reflection(s) of the emitted light from the user's eyes. Furthermore, reflections of the emitted light from the user's eyes are used as reference for determining the position of the pupils of the user's eyes with respect to the reflections.
However, there exist a number of limitations associated with implementations of the aforementioned gaze-tracking techniques. Firstly, a portion of the reflections may be occluded when the user's eyes are partially closed. In such an instance, some of the reflections may be absent (namely, some light may not be reflected by the surface of the user's eyes). Consequently, such occlusion of the reflections leads to inaccurate determination of the position of the pupils of the user's eyes. Secondly, since some of the reflections may be obscured by eyelids of the user, positions of the visible reflections may be inaccurately identified. Such inaccurate identification of the position of the visible reflections further leads to inaccuracies in gaze detection. Thirdly, various ambient light sources may be present near the user that may emit light towards the user's eyes. In such an instance, reflections of ambient light may be inaccurately considered to be reflections of the light emitted by the plurality of illuminators. Consequently, in such a case, the position of the pupils of the user's eyes is inaccurately determined. Fourthly, existing gaze-tracking techniques do not compensate for changes in pupil geometry (namely, on account of pupil contraction and pupil dilation). Consequently, additional inaccuracies (for example, such as geometric aberrations, reflection artefacts, and the like) are introduced whilst tracking the user's gaze.
Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with conventional gaze-tracking techniques.